Resolución de problemas reales en el aula : determinación experimental de vitamina C en zumos naturales.

Resumen tomado de la publicación

Efeito da vitamina K da dieta na anticoagulação oral crônica : evidências prospectivas observacionais e randomizadas

Base Teórica. Embora vários relatos de casos tenham sugerido uma associação entre a ingesta de vitamina K e a instabilidade da anticoagulação oral, o impacto clínico de diferentes quantidades de vitamina K dietética na anticoagulação oral crônica nunca foi prospectivamente estabelecido. Métodos. Características clínicas e estimativas semi-quantitativas sobre a ingesta de vitamina K foram avaliadas, prospectivamente, em 230 visitas ambulatoriais de pacientes anticoagulados em um hospital público universitário (protocolo observacional). Treze pacientes ambulatoriais anticoagulados cronicamente e estáveis foram arrolados em um ensaio clínico randomizado cruzado de intervenção dietética de 4 dias com aumento e diminuição de 5 vezes da sua ingesta habitual de vitamina K (protocolo experimental randomizado). Resultados. Protocolo observacional: Na análise univariada, identificamos uma associação estatisticamente significativa, progressiva e inversa entre um escore global de ingesta de vitamina K e diferentes níveis de anticoagulação. Na análise multivariada, a ingesta de vitamina K dietética foi independentemente associada com níveis subterapêuticos e anticoagulação excessiva (ambos valores de p =0,04), após ajuste para escolaridade, renda, uso de novos fármacos, aderência à anticoagulação oral e intercorrências clínicas. Protocolo randomizado: Após a dieta restrita em vitamina K, observamos um aumento significativo nos valores do INR (de 2,6 ± 0,5 para 3,3 ± 1,0, p=0,03; do início para o dia 7) enquanto, após a dieta enriquecida, identificamos uma diminuição significativa e mais precoce no INR (de 3,2 ± 0,9 para 2,8 ± 0,7, p=0,005; do início para o dia 4). O efeito da ingesta de vitamina K sobre a variação do INR foi particularmente influenciada pela ingesta média habitual da vitamina. Conclusões. Nossos dados prospectivos reforçam o conceito de que a interação vitamina K e fármacos cumarínicos é de fato real e clinicamente relevante, devendo ser reconhecida como um fator importante e independente que interfere com a estabilidade da anticoagulação oral crônica.

A influência da alimentação com diferentes níveis de vitamina E e selênio sobre a produção de imunoglobulina Y (IgY) no soro de poedeiras leves vacinadas contra Escherichia coli e encefalomielite aviária

Foram estudados os efeitos da suplementação de vitamina E (VE) e selênio (Se) sobre a imunidade de galinhas vacinadas contra Escherichia coli (EC) patogênica para suínos e com o vírus da encefalomielite aviária (VEA). Foram avaliados peso corporal (PC), peso de ovos (PO) e produção de anticorpos (AcP) em noventa poedeiras (H&N nick chick) com 49 semanas de idade alimentadas à vontade com dietas suplementadas com 0, 50, 150, 250 e 250 UI VE/kg + 0,3 ppm de Se. Às 51 semanas de idade, metade das galinhas foram vacinadas contra EC e todas as aves foram vacinadas contra VEA. Duas semanas após, receberam uma segunda dose da vacina contra EC. Amostras de sangue foram coletadas semanalmente e a quantidade de IgY foi determinada por ELISA, como densidade ótica (DO). As aves vacinadas apresentaram maior DO do que as aves não vacinadas (P≤0,05). As DO foram significativamente aumentadas (P≤0,05) quando as aves vacinadas foram alimentadas com 50 e 150 UI de VE/kg e comparadas com as DO das aves que receberam a dieta de 250 UI de VE + Se. Se não afetou AcP, PC e PO. A vacinação e a VE suplementada não afetaram PC. O PO não foi afetado pela vacinação, mas foi maior (P≤0,05) nas semanas 3, 5 e 7, quando as poedeiras receberam 250 UI VE/kg e comparados com aquelas que receberam 50, 150 e 0. A AcP contra VEA foi influenciada pela VE (P≤0,13). Cento e cinqüenta UI VE e 0 UI VE aumentaram IgY produzida, quando comparados a 250 UI. Também o Se aumentou AcP. Os resultados deste estudo sugerem que níveis médios de VE aumentam a produção de IgY por poedeiras vacinadas e Se adicionado ao mais alto nível de VE também possui efeito imunomodulador.

Suco de laranja e vitamina C : efeito sobre a estabilidade genômica

Existem evidências crescentes indicando a associação entre dietas ricas em frutas e vegetais e a diminuição da incidência de câncer. O suco de laranja (OJ) pode ser incluído entre os alimentos com potencial quimioprotetor e seu estudo é muito relevante pelo amplo consumo desta bebida. O OJ possui vários nutrientes e compostos bioativos com atividades antioxidante, antimutagênica, anticarcinogênica e antiaterogênica, entre outras. A vitamina C (Vit C) é um dos nutrientes mais abundantes no OJ, e o único nutriente que pode ser provido em quantidade superior à recomendação diária por uma única porção de 200 mL de OJ. A Vit C, a exemplo de outros componentes do OJ, pode ser tanto benéfica quanto maléfica para os sistemas biológicos, dependendo do contexto metabólico. Neste sentido, vários nutrientes presentes no OJ têm sido identificados como mutagênicos ou carcinogênicos, especialmente quando administrados de forma isolada. Este estudo utilizou o ensaio Cometa alcalino em sangue de camundongos (in vivo) para avaliar: 1) a genotoxicidade do OJ e da Vit C; 2) a genotoxicidade do FeSO4 e do CuSO4: 3) o efeito modulador do OJ e da Vit C sobre a genotoxicidade do FeSO4 e CuSO4, bem como do metilmetanosulfonato (MMS) e da ciclofosfamida (CP). A versão alcalina do ensaio Cometa foi utilizada para avaliar o dano no DNA em células brancas do sangue periférico de camundongos. Adicionalmente, os níveis de cobre e ferro no sangue e no fígado dos camundongos tratados com metais e OJ foram avaliados pela metodologia de PIXE (Particle-Induced X-ray Emission). Grupos com pelo menos 6 camundongos (metade de cada sexo) foram tratados por gavage com uma ou duas doses de água (controle), CP, MMS, FeSO4 ou CuSO4. OJ (0.1 mL/Kg) foi administrado tanto antes (pré-tratamento) quanto após a administração das substâncias-teste (pós-tratamento). A Vit C (1 e 30 mg/Kg) foi administrada apenas no pós-tratamento. O dano no DNA foi avaliado 24 e 48 h após o início do tratamento. Após 24 h, o OJ induziu um suave aumento no dano no DNA, enquanto a Vit C foi genotóxica (30 mg/Kg > 1 mg/Kg). O tratamento duplo com Vit C (a 0 e a 24 h) induziu uma resposta genotóxica cumulativa a 48 h, que foi mais intensa para a dose maior. O FeSO4 e o CuSO4 foram genotóxicos após 24 h, mas tiveram seu dano efetivamente reparado após 48 h do tratamento. O pré-tratamento com OJ reduziu a genotoxicidade do FeSO4 e do CuSO4 (efeito preventivo). O pós-tratamento com OJ também reduziu a genotoxicidade do CuSO4 (efeito reparador). O OJ mostrou tanto efeito preventivo quanto reparador sobre a genotoxicidade do MMS. O OJ teve apenas efeito reparador sobre a CP. Ambas doses de Vit C aumentaram os danos no DNA causados pelo FeSO4 e pelo CuSO4. Adicionalmente, os níveis de cobre e ferro no sangue e no fígado dos camundongos tratados com metais e OJ foram avaliados pela metodologia de PIXE (Particle-Induced X-ray Emission). Grupos com pelo menos 6 camundongos (metade de cada sexo) foram tratados por gavage com uma ou duas doses de água (controle), CP, MMS, FeSO4 ou CuSO4. OJ (0.1 mL/Kg) foi administrado tanto antes (pré-tratamento) quanto após a administração das substâncias-teste (pós-tratamento). A Vit C (1 e 30 mg/Kg) foi administrada apenas no pós-tratamento. O dano no DNA foi avaliado 24 e 48 h após o início do tratamento. Após 24 h, o OJ induziu um suave aumento no dano no DNA, enquanto a Vit C foi genotóxica (30 mg/Kg > 1 mg/Kg). O tratamento duplo com Vit C (a 0 e a 24 h) induziu uma resposta genotóxica cumulativa a 48 h, que foi mais intensa para a dose maior. O FeSO4 e o CuSO4 foram genotóxicos após 24 h, mas tiveram seu dano efetivamente reparado após 48 h do tratamento. O pré-tratamento com OJ reduziu a genotoxicidade do FeSO4 e do CuSO4 (efeito preventivo). O pós-tratamento com OJ também reduziu a genotoxicidade do CuSO4 (efeito reparador). O OJ mostrou tanto efeito preventivo quanto reparador sobre a genotoxicidade do MMS. O OJ teve apenas efeito reparador sobre a CP. Ambas doses de Vit C aumentaram os danos no DNA causados pelo FeSO4 e pelo CuSO4. processado e armazenado de forma a preservar o seu potencial biológico é um alimento sugerido como uma das porções de uma dieta equilibrada (contendo pelo menos 5 porções de frutas e vegetais), recomendada para uma vida saudável e longeva.

Barra "Vitamina"

Imagem componente do jogo “DigesTower (http://www.loa.sead.ufscar.br/digestower.php)” desenvolvido pela equipe do Laboratório de Objetos de Aprendizagem da Universidade Federal de São Carlos (LOA/UFSCar).

Vitamina

Imagem componente do jogo “DigesTower (http://www.loa.sead.ufscar.br/digestower.php)” desenvolvido pela equipe do Laboratório de Objetos de Aprendizagem da Universidade Federal de São Carlos (LOA/UFSCar).

Avaliação da suplementação materna com megadose de vitamina a sobre os níveis de retinol e alfa-tocoferol no colostro

The vitamins A and E are recognizably important in the initial stages of life and the newborn depends on nutritional adequacy of breast milk to meet their needs. These vitamins share routes of transport to the tissues and antagonistic effects have been observed in animals after supplementation with vitamin A. This study aimed to verify the effect of maternal supplementation with vitamin A megadose (200,000 UI) in the immediate post-partum on the concentration of alpha-tocopherol in colostrum. Healthy parturient women attended at a public maternity natalensis were recruited for the study and divided into two groups: control (n = 37) and supplemented (n = 36). Blood samples of colostrum and milk were collected until 12 hours after delivery. The women of the supplemented group was administered a retynil palmitate capsule and 24 hours after the first collection was obtained the 2nd sample of colostrum in two groups for analysis of retinol and alpha-tocopherol in milk. The mean retinol concentration of 50,7 ± 14,4 μg/dL (Mean ± standard deviation) and alpha-tocopherol of 1217.4 ± 959 mg/dL in the serum indicate the nutritional status biochemical appropriate. Supplementation with retynil palmitate resulted in increase not only retinol levels in the colostrum of the supplemented group (p = 0.002), but also the concentration of alpha-tocopherol (p = 0.04), changing from 1456.6 ± 1095.8 mg/dL to 1804.3 ± 1432.0 mg/dL (milk 0 and 24 respectively) compared to values in the control group, 984.6 ± 750.0 mg/dL and 1175.0 ± 730.8 mg/dL. The women had different responses to supplementation, influenced by baseline levels of retinol in colostrum. Those with previous by low levels of retinol in colostrum (<60 mg/dL) had increased the concentration of alpha-tocopherol in milk, whereas those with adequate levels (> 60 mg/dL), showed a reduction after supplementation. Supplementation with retinol palmitate is an important intervention in situations of high risk for vitamin A deficiency, when considering the need to maternal supplementation, since the excess vitamin can offer unfavorable interactions between nutrients essential for the mother-child group

Influência do estado nutricional materno em vitamina A sobre os níveis de imunoglobulina A no colostro humano

Mothers with good vitamin A nutritional status during gestation and lactation are better able to nourish and protect their infant with maternal milk. Our hypothesis is that women with more serum retinol have more retinol and secretory immunoglobulin A in colostrum. 190 healthy puerperal women from a Brazilian public maternity were recruited and divided according to the cutoff point for serum retinol (30 μg/dL). A number of the women was supplemented with 200000 UI (60 mg) of retinyl palmitate in the immediate postpartum. Serum and colostrum were collected on the 1st day postpartum and colostrum again on the following day. Retinol (serum and colostrum) was analyzed by HPLC and SIgA (colostrum) by turbidimetry. The mothers presented with adequate biochemical indicators of nutritional status, according to serum retinol (44.6 μg/dL). There were significant differences (p= 0.0017 and p= 0.043, respectively) in retinol and SIgA levels in the colostrum of mothers with serum retinol > 30 μg/dL and < 30 μg/dL. The concentration of SIgA in the colostrum of non-supplemented mothers on the 1st day postpartum was 822.6 mg/dL, decreasing after 24 hours to 343.7 mg/dL. Supplemented mothers showed levels of SIgA in colostrum of 498.9 mg/dL on the 2nd day postpartum (p= 0.00006). The colostrum of women with good vitamin A nutritional status had more retinol and SIgA. Additionally, maternal supplementation increases the levels of SIgA in colostrum. The higher levels of SIgA on the 1st day postpartum showed the importance of early breastfeeding, given that it provides considerable immunological benefits to newborn infants

Estado nutricional e efeito da vitamina A na resposta imune frente à infecção por Leishmania Infantum

Nutritional status is an important determinant to the response against Leishmania infection, although few studies have characterized the molecular basis for the association found between malnutrition and the disease. Vitamin A supplementation has long been used in developing countries to prevent mortality by diarrheal and respiratory diseases, but there are no studies on the role of vitamin A in Leishmania infection, although we and others have found vitamin A deficiency in visceral Leishmaniasis (VL). Regulatory T cells are induced in vitro by vitamin A metabolites and are considered important cells implicated T CD4+ cell suppression in human VL. This work aimed to examine the correlation of nutritional status and the effect of vitamin A in the response against Leishmania infantum infection. A total of 179 children were studied: 31 had active VL, 33 VL history, 44 were DTH+ and 71 were DTH- and had negative antibody to Leishmania (DTH-/Ac-). Peripheral blood monuclear cells were isolated in a subgroup of 10 active VL and 16 DTH-/Ac- children and cultivated for 20h under 5 different conditions: 1) Medium, 2) Soluble promastigote L. infantum antigens (SLA), 3) All-trans retinoic acid (ATRA), 4) SLA + ATRA and 5) Concanavalin A. T CD4+CD25highFoxp3+, T CD4+CD25-Foxp3- and CD14+ monocytes were stained and studied by flow cytometry for IL-10, TGF-β and IL-17 production. Nutritional status was compromised in VL children, which presented lower BMI/Age and retinol concentrations when compared to healthy controls. We found a negative correlation between nutritional status (measured by BMI/Age and serum retinol) and anti-Leishmania antibodies and acute phase proteins. There was no correlation between nutritional status and parasite load. ATRA presented a dual effect in Treg cells and monocytes: In healthy children (DTH-/Ac-), it induced a regulatory response, increasing IL-10 and TGF-β production; in VL children it modulated the immune response, preventing increased IL-10 production after SLA stimulation. Furthermore, we found a positive correlation between BMI/Age and IL-17 production and negative correlation between serum retinol and IL-10 and TGF-β production in T CD4+CD25highFoxp3+ cells after SLA stimulus. Our results show a potential dual role of vitamin A in the immune system: improvement of regulatory profile during homeostasis and down modulation of IL-10 in Treg cells and monocytes during symptomatic VL. Therefore, the use of vitamin A concomitant to VL therapy might improve recovery from disease status in Leishmania infantum infection

Avaliação da suplementação com vitamina E, na forma natural ou sintética, em mulheres no pós-parto imediato e sua concentração no colostro

The Vitamin E consists of eight chemically homologous forms, designated alpha, beta, gamma and delta tocopherols and tocotrienols. Biologically, the alpha-tocopherol (α-TOH) is the most important. Commercially, are found two types of α-TOH a natural (RRR-alpha-tocopherol) and another synthetic (all-rac-alpha-tocopherol). Both forms are absorbed in the intestine, the liver is a preference in favor of forms 2R, due to transfer protein α-TOH. It has higher affinity to these stereoisomers. Newborns are considered high risk for vitamin E deficiency, mainly premature, these have breast milk as a food source for maintenance of serum α-TOH. Clinical signs such as thrombocytosis, hemolytic anemia, retrolental fibroplasia, intraventricular hemorrhage, bronchopulmonary dysplasia and spinocerebellar degeneration can be found in case of a low intake of α-TOH. Thus, maternal supplementation on postpartum with α-TOH can be an efficient way to increase levels of vitamin E in breast milk and thus the consequently increase the supply of micronutrient for the newborn. However, most studies with vitamin E supplementation have been conducted in animals and little is known about the effect of maternal supplementation in humans, as well as on its efficiency to increase levels of α-TOH in human milk, depending on the shape natural or synthetic. The study included 109 women, divided into three groups: control without supplementation (GC) (n=36), supplemented with natural capsule (GNAT) (n=40) and the synthetic capsule (GSINT) (n=33). Blood samples were collected for determination of maternal nutritional status, and colostrums at initial contact and after 24 hours post-supplementation. Analyses were performed by High Performance Liquid Chromatography. Values of α-TOH in serum below 499.6mg/dL were considered deficient. We used the Kruskal-Wallis test and Tukey test to confirm the increase of alpha-tocopherol in milk and efficiency of administered capsules. Daily consumption of α-TOH was based on daily intake of 500 mL of colostrum by the newborn and compared with the nutritional requirement for children from 0 to 6 months of age, 4 mg / day. The mothers had mean concentration of serum α-TOH in 1016 ± 52, 1236 ± 51 and 1083 ± 61 mg / dL, in CG, GNAT and GSINT respectively. There were no women with deficiiency. The GC did not change the concentrations of α-TOH in colostrum. While women supplemented with natural and synthetic forms increased concentrations of α-TOH colostrum in 57.6% and 39%, respectively. By comparing supplemented groups, it was observed a significant difference (p=0.04), the natural capsule more efficient than the synthetic, approximately 49.6%. Individually, 21.1% of the women provided below 4mg/day of α-TOH, after supplementation for this index declined4.1%. Thus, maternal supplementation postpartum raised the levels of alpha-tocopherol in colostrum, and increased efficiency was observed with the natural form

Avaliação do efeito da megadose de vitamina A no colostro humano

The mothers supplementation of vitamin A in the postpartum comes being a measure of intervention sufficiently used in the combat to the vitamin deficiency. The objective of this work was to evaluate the effect of the mother megadose of vitamin A under the levels of retinol in colostrum of postpartum mothers receiving care at the Januário Cicco Maternity School (MEJC), Natal, RN, as well as analyzing the influence of the maternal nutritional status in the reply to this supplementation. The study it was transversal type, with participation of 91 women in labor divided in group had participated of the study have controlled (44 women) and supplemented group (47 women). In the period of the morning blood and milk had been collected (milk 0h). After that a capsule of retinil palmitate of (200 000 UI or 60 mg) was supplied to the supplemented group. Another aliquot of colostro was after gotten 24h of the first collection (milk 24h). Retinol in milk and serum was quantified through the High Pressure Liquid Chromatography. The vitamin ingestion was evaluated by the questionnaire of frequency of alimentary consumption. The levels of serum retinol were 40.6 ± 10.6 and 35.9 ± 10.9 µg/dL in the groups controlled and supplemented, respectively. The women had presented a satisfactory average ingestion of vitamin (1492,4 µgRAE/dia), however with high prevalence of inadequate consumption (23%). Average values of retinol in milk 0h had been found and 24h of 93.5 ± 50.3 µg/dL and 99.1 ± 49.3 µg/dL has the group controlled group, respectively (p>0.05). After the supplementation had a significant increase in the levels of retinol of the supplemented group, being found values of 102.0 ± 56.0 µg/dL and 196.1 ± 74.0 µg/dL for milk 0h and 24h, respectively (p<0.0001). The women in labor presented different answers to the supplementation influenced for the basal levels of retinol in colostrum. It was possible to verify that women with deficient levels of retinol in milk had transferred more retinol to milk 24h than ones with adjusted levels, showing a percentage of reply equivalent to 326.1% and 86.5% of increase, respectively (p< 0.0001). Although the apparent normality found in the serum, the studied women are considered of risk to the development of the vitamin deficiency, and megadose was efficient in first 24h after the supplementation and wakes up with the mechanisms considered for transference of vitamin A to the milk

Influência da suplementação de retinol palmitato sobre os níveis de vitamina A no leite de puérperas saudáveis

The tendency towards reduction of serum retinol levels, an existing placental barrier and the increase of retinol demand, are factors that place puerperal and lactating women at risk for Vitamin A deficiency. This micronutrient is an essential component of vital processes such as differentiation, cellular proliferation, and apoptosis. The objective of this study is to evaluate the effect of palmitate retinol supplementation (100.000UI) upon the milk retinollevels in puerperal women at the Januário Cicco University Maternity Hospital. This intervention has been adopted by the Ministry of Health since 2002. The longitudinal experiment was conducted with 106 puerperal women (68 comprised the supplemented group and 38 the control group). The High Performance Liquid Chromatography (HPLC) method was used to dose the retinol of the milk and serum samples, and the creamtocrit method to determine the milk fat levels. The retinol means for the colostrums were 99.0 ± 64.4 ug/dL and 160.1 ± 94,4 ug/dl 6 hours afier supplementation; 68.9 ± 33.5 ug/dL for the transitional milk, and 30.6 ± 15.2 ug/dL for the mature milk of the supplemented group. Ali the difterences between means were statistically significant. The difterence between retinol means in the control group were also significant, with these being greater in the colostrum, 88.6 ± 62.1 ug/dL with 61.9 ± 30.1 ug/dl in the transition milk and 32.9 ±32.9 ± 17.6 ug/dL in the mature milk. No significant difference was observed in the retinol means of the three types ot milk in the supplemented group when compared to their respective means in the control group. The prevalence in serum (35.1 % and 81.1 % for the cutting point 20 ug/dL, respectively) and in milk (51.4%) revealed vitamin A deficiency as a public health problem. COlostrum, transition, and mature milk tats varied similarly in the supplemented group (1,92 ± 0,96; 3,25 ± 1,27 and 3,31 ± 1,36 grams) and in the control group (1,87 ± 1,14; 3,25 ± 1,31 and 3,36 ± 1,67 grams), with an observed difference between the colostrum/transition milk and the colostrum/mature milk fats. No difference was observed between the groups. The study showed that the 200.000UI supplementation was not sufficient to increase the milk retinol to the desired levels nor to meet the demands of the mothers with deprived hepatic reserves. It is suggested that another similar dose be offered within 30 days or less, and within 2 months post-partum, while continual/y monitoring for possible pregnancy

Efeitos da deficiência de vitamina A na função pulmonar de crianças após infecção respiratória viral

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